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I have a lot of points' coordinates. I drew them on a 2d plot with ListPlot, and the points cover an area. Then I need to get the region that cover these points. Is there a way to do that? Thanks.

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  • $\begingroup$ You mean the minimum-area convex region that includes all the points. (This is the ConvexHull.) $\endgroup$
    – David G. Stork
    Commented Feb 12, 2015 at 23:40

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I'm pretty sure that you are asking about convex region. Without this statement one can draw very weird region:

SeedRandom[1];
pts = RandomReal[{-1, 1}, {50, 2}];
Show[Graphics@{LightBlue, EdgeForm@Lighter@Blue, 
   Polygon@Deintersect[pts]}, ListPlot[pts]]

enter image description here

Deintersect is defined here.

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ConvexHullMesh :

pts = RandomReal[{-1, 1}, {50, 2}];

Show[ConvexHullMesh[pts], ListPlot[pts]]

enter image description here

For earlier versions see ConvexHull.

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Yet another area defined by the list of points:

SeedRandom[1];
pts = RandomReal[{-1, 1}, {50, 2}];
Graphics[{Blue, Point @ pts,
  LightBlue, EdgeForm @ Gray, Polygon @ pts[[FindShortestTour[pts][[2]]]]}]

enter image description here

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